Optoelectronic Devices Based on Atomically Thin Transition Metal Dichalcogenides

Pospischil, Andreas; Mueller, Thomas

doi:10.3390/app6030078

Cited by 105 publications

(73 citation statements)

References 132 publications

(191 reference statements)

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“…Atomically thin semiconductors, such as transition metal dichalcogenides (TMDs), have revolutionized research in optics and electronics [1][2][3][4][5]. Alongside with the tremendous potential for innovative technologies, their optical and electronic properties further allow to study fundamental many-particle processes in an unprecedented scope.…”

Section: Introductionmentioning

confidence: 99%

Exciton Relaxation Cascade in two-dimensional Transition Metal Dichalcogenides

Brem

Selig

Berghaeuser

et al. 2018

Sci Rep

107

142

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Monolayers of transition metal dichalcogenides (TMDs) are characterized by an extraordinarily strong Coulomb interaction giving rise to tightly bound excitons with binding energies of hundreds of meV. Excitons dominate the optical response as well as the ultrafast dynamics in TMDs. As a result, a microscopic understanding of exciton dynamics is the key for a technological application of these materials. In spite of this immense importance, elementary processes guiding the formation and relaxation of excitons after optical excitation of an electron-hole plasma has remained unexplored to a large extent. Here, we provide a fully quantum mechanical description of momentum- and energy-resolved exciton dynamics in monolayer molybdenum diselenide (MoSe2) including optical excitation, formation of excitons, radiative recombination as well as phonon-induced cascade-like relaxation down to the excitonic ground state. Based on the gained insights, we reveal experimentally measurable features in pump-probe spectra providing evidence for the exciton relaxation cascade.

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Section: Introductionmentioning

confidence: 99%

Exciton Relaxation Cascade in two-dimensional Transition Metal Dichalcogenides

Brem

Selig

Berghaeuser

et al. 2018

Sci Rep

107

142

View full text Add to dashboard Cite

show abstract

“…The confinement of correlated charge carriers or excitons to a narrow region of space in low dimensional transition metal dichalcogenides (TMDCs) leads to unique photoluminescence properties [13][14][15][16][17][18][19][20][21][22] that are otherwise absent in the bulk configurations [23]. The availability of state-of-the art exfoliation techniques [24][25][26][27] enable fabrication of low dimensional transition metal dichalcogenides that is useful for applications [13,15,[28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43].…”

Section: Introductionmentioning

confidence: 99%

Exciton formation assisted by longitudinal optical phonons in monolayer transition metal dichalcogenides

Thilagam

2016

Journal of Applied Physics

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We examine a mechanism by which excitons are generated via the LO (longitudinal optical) phonon-assisted scattering process after optical excitation of monolayer transition metal dichalcogenides. The exciton formation time is computed as a function of the exciton center-of-mass wavevector, electron and hole temperatures, and carrier densities for known values of the Fröhlich coupling constant, LO phonon energy, lattice temperature, and the exciton binding energy in layered structures. For the monolayer MoS2, we obtain ultrafast exciton formation times on the sub-picosecond time scale at charge densities of 5 × 10 11 cm −2 and carrier temperatures less than 300 K, in good agreement with recent experimental findings (≈ 0.3 ps). While excitons are dominantly created at zero center-of-mass wavevectors at low charge carrier temperatures (≈ 30 K), the exciton formation time is most rapid at non-zero wavevectors at higher temperatures (≥ 120 K) of charge carriers. The results show the inverse square-law dependence of the exciton formation times on the carrier density, consistent with a squarelaw dependence of photoluminescence on the excitation density. Our results show that excitons are formed more rapidly in exemplary monolayer selenide-based dichalcogenides (MoSe2 and WSe2) than sulphide-based dichalcogenides (MoS2 and WS2).

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“…TMDs have recently gained much attention because of their potential applications in electronics [8][9][10][11] and optoelectronics [8, [12][13][14]. At monolayer thickness, TMDs can exhibit direct electronic and optical bandgaps ranging from the visible to the near-infrared.…”

Section: Case Study 1 Transmission Characterization Of 2d Transitionmentioning

confidence: 99%

Micro-Extinction Spectroscopy (MExS): a versatile optical characterization technique

Kumar

Villarreal

Zhang

et al. 2018

Adv Struct Chem Imag

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Micro-Extinction Spectroscopy (MExS), a flexible, optical, and spatial-scanning hyperspectral technique, has been developed and is described with examples. Software and hardware capabilities are described in detail, including transmission, reflectance, and scattering measurements. Each capability is demonstrated through a case study of nanomaterial characterization, i.e., transmission of transition metal dichalcogenides revealing transition energy and efficiency, reflectance of transition metal dichalcogenides grown on nontransparent substrates identifying the presence of monolayer following electrochemical ablation, and scattering to study single plasmonic nanoparticles and obtain values for the refractive index sensitivity and sensing figure of merit of over a hundred single particles with various shapes and sizes. With the growing integration of nanotechnology in many areas, MExS can be a powerful tool to both characterize and test nanomaterials.

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Optoelectronic Devices Based on Atomically Thin Transition Metal Dichalcogenides

Cited by 105 publications

References 132 publications

Exciton Relaxation Cascade in two-dimensional Transition Metal Dichalcogenides

Exciton Relaxation Cascade in two-dimensional Transition Metal Dichalcogenides

Exciton formation assisted by longitudinal optical phonons in monolayer transition metal dichalcogenides

Micro-Extinction Spectroscopy (MExS): a versatile optical characterization technique

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